Garage door operator safety apparatus

ABSTRACT

A garage door opening and closing apparatus having improved operational safety is disclosed. The apparatus includes a control circuit which responds to a number of input stimuli to generate commands to open and close a garage door as well as to stop garage door movement. Three relays respond to the commands via drive circuitry to actually connect door operating voltages to the windings of a door controlling motor. By redundancies in the operation of the three relays, faults in the operation of those relays result in safe door operating conditions. Additionally, the control circuitry upon issuing a door stop command, performs a test to determine whether or not the door is still moving. If the door is still moving, door up commands are generated by the control circuitry to place the door in a safe position.

This is a Continuation of prior application Ser. No. 08/823,727, filedMar. 25, 1997, now U.S. Pat. No. 5,841,253, which is a Continuation ofapplication Ser. No. 08/588,227, filed Jan. 18, 1996, now U.S. Pat. No.5,684,372, which is a Continuation of application Ser. No. 08/465,606,filed Jun. 5, 1995, now abandoned, which is a Continuation ofapplication Ser. No. 08/367,920 filed Jan. 3, 1995, now abandoned, whichis a Continuation of application Ser. No. 08/200,292, filed Feb. 22,1994, now abandoned, which is a Continuation of application Ser. No.07/964,566, filed Oct. 21, 1992, now abandoned, which is a Continuationof application Ser. No. 07/682,671, filed Apr. 9, 1991, now abandoned,which are hereby incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

This invention relates to door opening and closing apparatus andparticularly to methods and apparatus for improving the operationalsafety of door opening and closing apparatus.

A garage door operator for opening and closing doors typically includesan electrical motor having an up winding and a down winding. When the upwinding is energized by an operating voltage, the motor shaft rotates inone direction to raise the floor and when the down winding is energizedby the operating voltage, the motor shaft rotates in the oppositedirection to lower the door. A control unit responds to external stimulisuch as door open and close request signals by energizing the properwinding to serve the request. The actual connection of the operatingvoltage to the up and down windings is provided by a pair of relays, oneassociated with each winding, the relays respond to signals from thecontrol unit by connecting the source of operating voltage to theirassociated windings. The control unit frequently comprises integratedcircuit logic which individually operates the relays via relay drivers.

Integrated circuit logic is subject to faults as are relay drivers andrelays themselves. Thus, improper relay control signals can be generatedby the integrated circuit logic or proper control signals can beinappropriately responded to by the drivers and relays. Although suchfaulty operation is infrequent, the effects of such are to be avoided,since they can, in extreme situations, cause injury to people in thevicinity of the apparatus.

The problem of faulty operation has been recognized and systems devisedto protect individuals from faulty operation. U.S. Pat. No. 4,338,553 toScott, discloses an apparatus which, when a door limit controllingoscillator fails, generates relay control signals to move a door to theup position. The Scott arrangements checks only the proper oscillatoroperation, and does not determine proper door operation in response togenerated control signals. U. K. Patent Application No. 2 072 884 toMatsuoka, et al., discloses an apparatus which uses timers to check forproper door operation. When a door operation such as opening the door,is not completed within a period of time, e.g., 23 seconds, representingthe maximum time for the completion of the operation, the timer signalsa fault and remedial action is taken. The remedial action is to removethe driving voltage from both up and down motor windings by means of afirst relay and to energize the up winding by means of a second relay.Importantly, no fault will be sensed by the disclosed arrangement untila door movement should be completed, e.g., 23 seconds, by which, timeinjury may have occurred. Also importantly, the additional relays andcircuitry required for the response to faulty door operation are notnormally exercised so that faults within them will remain untested andthe additional relays and circuitry add to the expense and complexity ofthe apparatus.

Known fault protection systems for garage door operators do not detectinappropriate door movement rapidly enough, are not tested by normaloperation, and add unnecessarily to the expense and complexity of theoverall apparatus.

SUMMARY OF THE INVENTION

The present invention solves the problems of prior systems by rapidlysensing inappropriate door movement and terminating such inappropriatemovement using a minimum amount of additional circuitry, which isroutinely exercised to protect against latent faults. The apparatus ofthe present invention includes circuitry for sensing the rotation of thedoor driving motor shaft and checking such rotation after issuing dooroperating commands. When the measured rotation is not appropriate forthe last door operating command, fault control signals are generated.The door controlling circuitry of the apparatus includes three (3) doorcontrolling switch arrangements for selectively energizing the up anddown motor windings of the door driving motor. A control unit operatesin cooperation with the motor shaft rotation sensor to detect improperdoor movement and to control the switching circuits to stop and move thedoor up. Upward movement of the door is assured when faced with anysingle fault in the door control circuitry.

An apparatus for opening and closing a garage door in accordance withthe present invention comprises a motor with a rotatable member forrotating in a first direction to open the garage door and in a seconddirection to close the garage door, and motor control circuitryresponsive to control commands for selectively connecting electricalpower to the motor to cause rotation of the rotatable member. A controlarrangement, shown in the embodiment as a logic unit, responds toexternal stimuli by selectively sending control commands specifyingrotation of the rotatable member in the first direction, rotation of therotatable member in the second direction or no rotation by the rotatablemember. After predetermined control commands, the actual rotation of therotatable member is sensed and when actual sensed rotation is not inaccordance with the last control command, fault control signals are sentto the motor control circuitry. The fault control signals can be used tocause the motor to raise the door to its safe upper limit.

Advantageously, the motor control circuitry comprises a plurality ofrelays which cooperate to provide safe operation of the door when faultsoccur within the motor control circuitry. In the preferred embodiment,the motor includes up and down windings for controlling the twodirections of rotatable member rotation. The motor control circuitryincludes a first relay which responds to control commands by connectingelectrical power to either the up motor winding or to an intermediateconductor. A second relay responds to control commands by selectivelyconnecting the intermediate conductor from the first relay to the downwinding, and a third relay responds to control commands by connectingelectrical power to the up winding. By this interconnection of relays,door movement can always be stopped and in most situations, it will bestopped in the upmost door position.

The logic unit of the embodiment responds to the external stimuli bygenerating upward movement control commands, downward movement controlcommands and door stop commands. When the door movement after a commandis not in accordance with the command, the logic unit generates faultcontrol signals which cause upward movement of the door.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the garage door operator of the invention installedto operate a garage door;

FIG. 2 is a block diagram of a control circuit of the garage dooroperator;

FIG. 3 illustrates the control of limit switches by a rotatable memberof a garage door operator;

FIG. 4 illustrates a garage door operator motor and rotation determiningapparatus; and

FIG. 5 is a state diagram of the operation of the garage door operatorcontrol circuit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates the garage door operator 10 of the inventioninstalled to move a garage door 14 positioned proximate with a dooropening 14a, which is mounted on tracks in a conventional manner. A headunit 11 of the garage door operator 10 includes a motor (211 FIG. 4),which is mounted in the head unit and has an output which drives anendless chain 15. A trolley 13 is engageable with the chain 15 and moveson a rail 12. Trolley 13 includes an arm 16 which is connected by abracket 17 to the door 14 to move the door up and down. A control unit19 is connected by an electrical cable 22 to control circuitry mountedin head unit 11. Control unit 19 has a plurality of buttons which can beactuated for the control of the garage door operator 10. A transmitter24 can be used to actuate the garage door operator 10 remotely bytransmitting a radio signal which is received by a receiver mounted inthe head unit 11.

FIG. 2 is a block diagram of the control circuit contained in head unit11. The control circuit includes a multi-function integrated circuitlogic unit 101, which responds to a plurality of inputs in the mannerdiscussed below, by selectively sending one of a plurality of motorcontrol commands to motor control circuitry 147 to control the openingand closing of the garage door. Power is supplied to the circuitry ofFIG. 2 from a transformer and diode combination (not shown) which supplyapproximately 28 volts DC to a positive terminal 102a of a capacitor102. The 28 volt DC is also coupled to a 5 volt regulator 103 whichproduces approximately 5 volts for use by the integrated circuit logic101 and certain of the circuits connected thereto.

One input to logic 101 is a command signal CMD-R on a conductor 105 froma receiver/decoder 106. The receiver/decoder 106 receives an encodedelectromagnetic radiation signal from the remote transmitter 24 at anantenna 107, detects the received encoded signal and verifies accuracyof the detected signal by comparing it to one or more stored permittedcode words. When signal detected by receiver/detector 106 matches apermitted code word stored within the receiver/detector, a transitorylogic 1 signal is sent to logic unit 101 via conductor 105, as thesignal CMD-R. The details of code reception from remote transmitters andthe verification of received codes are described in detail in U.S. Pat.No. 4,750,118 to Heitschel, et al., and application Ser. No. 626,909 toHeitschel, et al.

Another command signal, CMD-P, is a transitory logic 0 which is appliedto logic 101 via a conductor 108, when a push-button 39 is pressed atcontrol unit 19. The signals CMD-R and CMD-P are the primary operatorcontrolled input signals to logic unit 101. The signal CMD-R indicatesthat a verified code was detected by receiver/detector 106 and thesignal CMD-P indicates that push button 39 was pressed. As discussed ingreater detail later herein, logic unit 101 interprets the receipt ofthese signals based on the state of the logic unit when they arereceived to control the operation of door 14. Other input signals suchas signals from an up limit switch 110 and a down limit switch 111 areprovided by the operation of the door opening and closing apparatusitself.

Up and down limit switches 110 and 111 are contained in head unit 11 andare controlled by an assembly 200 shown in FIG. 3. The limit switchassembly 200 of FIG. 3 includes a threaded drive shaft 201, which isattached to (not shown) and rotated by a motor 211 through a gear 203.Gear 203 is connected to the shaft 201 of driving motor 211 so that therotation of the motor shaft 213 causes the rotation, of threaded driveshaft 201. A switch actuating member 205 having an threaded aperturetherethrough is threaded onto drive shaft 201 and kept from rotating bya securing member 207. When the motor 211 is energized to rotate in adirection to raise the door 14, shaft 201 rotates in a first directionand the actuation member 205 rises by the rotation of the shaft 201acting through the threads. Similarly, as the motor shaft 213 and theshaft 201 rotate in the reverse direction, actuating member 205 travelsdownwardly. Actuating member 205 includes a protruberance 209 whichengages and closes up limit switch 110 at the top of door travel and atthe bottom of door travel, engages and closes down limit switch 111.When the door opening apparatus 10 of FIG. 1 is first fitted to the door14, the positions of limit switches 110 and 111 are adjusted so thatdown limit switch 111 closes when the door 14 is in its maximum closedposition and up limit switch 110 closes when the door 14 is in itsmaximum open or raised position. After initial adjustment, maximum openposition is determined when the up limit switch 110 connects anelectrical ground 112 to an up limit conductor 113 and the maximum downposition is detected when switch 111 connects electrical ground 112 to adown limit conductor 115. Up limit conductor 113 and down limitconductor 115 are connected as inputs UL and DL, respectively to logicunit 101.

The apparatus of FIG. 2 also includes an infrared obstruction detector117. Obstruction detector 117 transmits an infrared light beam from oneside of the door opening 14a to the other at a suitable height, such asone foot, in order to detect people or objects which might be contactedby a closing door. Normally, the infrared beam will pass freely from oneside of the door opening 14a to the other and, the obstruction detector117 will send a low logic level signal to the base of an NPN transistor119. The low logic level signal will not turn transistor 119 on and anapproximately 5 volt signal is applied to an input AOBS of logic unit101, via conductor 120 and the operation of resistors 121 through 123,energized by a positive 28 volt potential. Alternatively, when theinfrared beam strikes an object in the doorway and does not pass fromside to side, a logic high signal is applied to the base of transistor119, resulting in a signal near electrical ground being applied to theinput AOBS of logic unit 101.

Logic unit 101 also receives at an input RPM a signal indicative of therotation of the shaft 213 of motor 211. FIG. 4 shows motor 211 and anapparatus 214 for sensing the rotation of its shaft 213. A disk 215 isattached to shaft 213 normal to the shaft's its access of rotation. Fivelight obstructing pins 217 are attached to the disk 215 in equallyspaced relationship a common distance from the center of shaft 213. Alight transmitting element, such as a light emitting diode 127, isfixedly attached to the same substrate as the motor 211 and in aposition between the pins 217 and the center of shaft 213. A lightreceiver, such as a phototransistor 128, is attached outside the circletraced by pins 217 to receive light from the light emitting diode 127.As the motor shaft 213 rotates, light is transmitted from light emittingdiode 127 to a base 128a of a phototransistor 128 when no pin istherebetween and no light is passed when a pin 217 is present betweenlight emitting diode 127 and phototransistor 128. The electricalconnections from light emitting diode 127 and phototransistor 128 areshown in FIG. 2. When motor shaft 213 is rotating, light willalternately be blocked and passed between light emitting diode 127 andthe base of phototransistor 128, causing phototransistor 128 toalternately be turned on and off. By connection to a 5 volt supplythrough a resistor 129, a square wave is applied by phototransistor 128to conductor 125, when motor shaft 213 is rotated. Conductor 125 isconnected to the input RPM of logic unit 101. The duty cycle of thesquare wave applied to the input RPM is determined by the spacingbetween pins 217 relative to the diameter of pins 217, and is notcritical in the present invention.

The signal from phototransistor 128 is also applied via conductor 125 toa pulse counter 251 and a monostable multi-vibrator 252. Pulse counter251 is used to generate and transmit a signal MOV to logic unit 101 onconductor 256 when the motor shaft 213 is rotating at or above apredetermined rate. The pulse counter 251 includes a resettable binarypulse counter which counts each low to high transition on conductor 125and records the count in binary format in an 8-bit shift register (notshown). When the shift register counts 25 or more transitions withoutbeing reset, a logic 1 signal is sent by the pulse counter 251 via theconductor 256 to the MOV pin of the logic unit 101. Logic unit 101comprises an internal oscillator and circuitry for generating a numberof timing signals. The period of the oscillator is determined by thevalue of a resistor 254 and a capacitor 255 connected between ground andterminals OSC 1 and OSC 2 of the logic unit 101. One timing signal isgenerated by the logic unit 101 every 0.5 seconds and is applied as areset signal to pulse counter 251 via a conductor 257. The register ofpulse counter 251 is cleared to zero in response to each reset signal.Thus, the value counted by counter 251 will exceed 25 only if 25 or morelow to high transitions occur on conductor 125 during a 0.5 secondinterval. That is, when shaft 213 is not rotating or rotating at a ratewhich causes fewer than 25 transitions during each 0.5 second interval,no signal MOV will be received at the MOV terminal by logic unit 101,because pulse counter 251 will be reset prior to its counting to 25.Alternatively, a signal MOV will be received by logic unit 101 whenshaft 213 is rotating at a rate which produces greater than 25 pulseseach 0.5 second.

Monostable multi-vibrator 252 is used to determine the movementresistance forces applied to the door during its movement. When themovement resistance forces exceed a predetermined amount, as forceobstruction signal OBS is applied by monostable 252 to logic unit 101via a conductor 258. The basic principle of operation is that the rateof rotation of the door motor shaft 213 decreases as the resistanceforces on the door increase. Monostable 252 is set by potentiometer 253to generate a pulse OBS on conductor 258 at a predetermined intervalunless the monostable is reset by a low to high transition of the signalon conductor 125 during an interval. When monostable 252 is reset,timing for a new pulse begins again. In the present embodiment,monostable 252 is adjusted by potentiometer 253 to produce a pulse onconductor 258 25 milliseconds after being reset by the signal onconductor 125. When the rotation of motor shaft 213 causes thephototransistor 128 to produce pulses on conductor 125 at intervals lessthan 25 milliseconds, monostable 252 will continue to be reset therebywithout generating a signal OBS on conductor 258. Alternatively, shouldthe motor shaft rotation rate slow sufficiently that the pulses aregenerated on conductor 125 at intervals greater than 25 milliseconds,monostable 252 will time out and generate a signal OBS on conductor 258.

Pulse counter 251, monostable 252 and their associated circuitry areshown separated from logic unit 101. The functions of these devicescould be incorporated into the single integrated circuit of logic unit101 such that the signals MOV and OBS would be generated entirelyinternal to the logic unit 101.

Logic unit 101 responds to the previously described input signals bysending a selected one of a plurality of motor control commands to motorcontrol circuitry 147 including three relays 130, 131 and 132, therebyopening and closing door 14 on command. Door motor 211 includes an upwinding 225 connected between an incoming motor conductor 220 and common221 by a thermal reset switch 229 and a down winding 227 which isconnected between an incoming motor conductor 222 and common 221 via thethermal reset switch 229. Door 14 is controlled to move up byselectively connecting 120 volts AC to up winding 225 via the conductor220 and is controlled to move down by the connection of 120 volts AC todown winding 227 via conductor 222. The selective connection of the 120V operating voltage to the up and down windings 225 and 227 is performedby motor control circuitry relays 130, 131 and 132 which operate inresponse to control commands from logic unit 101.

Relay 130 includes a normally open contact set 136 which is connected inseries between the 120 volt operating voltage applied to a conductor 134and both the up winding 225 and a normally open contact 138 of relay131. The state of relay 130 is controlled by signals from logic unit 101on a conductor 140. When the UPMTR2 signal on conductor 140 from logicunit 101 is a low level, a transistor 141 which has itsemitter-collector path connected in series with the coil of relay 130 isin a high impedance state and relay 130 is not energized. Alternatively,when the signal UPMTR2 from logic unit 101 is a high level, transistor141 is driven to a low impedance state energizing the relay 130 andclosing contact set 136 so that the 120V AC potential is supplied to upwinding 225.

The relay 131 includes an armature 137 which is connected to the 120volt conductor 134, a normally open stationary contact 138 and anormally closed stationary contact 139. The particular one of stationarycontacts 138 and 139 which is connected by armature 137 to the 120 voltsupply, is determined by signal UPMTR1 from line unit 101 on conductor142. In a manner similar to the operation of relay 130, relay 131 isenergized and de-energized by the operation of transistor 143 inresponse to the signal UPMTR1. The normally closed contact 139 connectsthe 120 volt conductor 134 to armature of relay 132 while the normallyopen contact 138 of relay 131 is connected to up winding 225 viaconductor 220.

Relay 132, which is controlled by a signal DWNMTR on a conductor 144operating through a transistor 145, includes a normally open stationarycontact set 146 connected in series with down winding 227. Wheneverrelay 132 is non-energized, no voltage is applied to the down winding227. Alternatively, when relay 132 is energized either the 120 voltconductor 134 or an open circuit is applied to down winding 227,depending on the state of relay 131.

The connection and operation of relays 130 through 132 provides certainredundancies in operation so that no single fault from the logic unit101 through the relays 130 through 132 will prevent the door 14 frommoving to the up position, which is considered safe. Logic unit 101generates motor control commands consisting of the signals shown inTable 1 to control the movement of door 14 up and down and to stop thedoor. The door 14 is moved up by sending high level (logical 1) signalson both UPMTR1 and UPMTR2 and a low level (logical 0) signal on DWNMTR.Both relays 130 and 131 are energized by the up signals whichredundantly apply 120 volts to up winding 225 via contact 136 of relay130 and contact 138 of relay 131. Also, energizing relay 131 removes theconnection of 120 volts to the down direction controlling relay 132.

The door 14 is moved down by energizing relay 132 while de-energizingrelays 130 and 131. De-energizing relay 131 connects the 120 volts fromconductor 134 to the armature of relay 132 which is connected to downwinding 227 by closure of relay 132. In the stop condition, none of therelays 130 through 131 is energized and neither of the motor windings225 or 227 receives the 120 volts from conductor 134.

                  TABLE 1                                                         ______________________________________                                        MOTOR CONTROL                                                                 COMMAND     UPMTR1      UPMTR2   DWNMTR                                       ______________________________________                                        Up          1           1        0                                            Down        0           0        1                                            Stop        0           0        0                                            ______________________________________                                    

FIG. 5 is a state diagram showing the various states of the logic unit101 and the inputs thereto which cause state changes. In the followingdescription, it is assumed that the up and down limit switches 110 and111 are properly set, that the movement force adjustment is set bypotentiometer 253 and that the garage door operator 10 has just beenpowered up. Also, in the terminology of FIG. 5, any signal with a barabove it refers to the absence of that signal and the term CMD refers toeither a command signal CMD-P from control unit 19 or a command signalCMD-R from the receiver/decoder 106.

Upon power up, an idle state 150 (FIG. 5) is entered. The idle state 150is the normal waiting state when the door 14 is at its up or down limit.In the idle state, the stop signals of Table 1 are sent to controlrelays 130 through 132 via respective driver transistors 141, 143 and145. When the circuitry and relays are operating without fault, the stopsignals de-energize the windings 225 and 227 of motor 211 and motorshaft 213 is stationary. For reasons of safety, the rotation of motorshaft 213 is checked whenever the motor 211 is commanded to stop. Whenthe rotation indicating signal MOV is detected by logic unit 101 onesecond after generating the stop command, control is transferred to themove up state 154 where the door 14 is raised to its safe upper limitposition, if possible. When the motor 211 does stop rotating in responseto the stop command, control remains in a loop 152 of the idle state 150as long as no command is received (CMD) or as long as both the up anddown limit signals (DL:UL) are received. Simultaneous up and down limitsignals indicate a fault and no door movement is initiated during suchconditions.

Assuming that the simultaneous UL and DL signals do not exist, controlleaves the idle state 150 when either command signal CMD-R or CMD-P isreceived. When the command is a CMD-P signal, logic unit 101 checkswhether the door 14 is at its up limit UL or its down limit DL asindicated by the states of up and down limit switches 110 and 111. Ifthe door 14 is at the down limit DL, control proceeds from the idlestate 150 to a move up state 154 via a path 156. In the move up state154, the up signals of Table 1 are sent to control relays 130 through132 and a loop 158 is entered. When the up limit UL is reached withoutencountering a force obstruction (OBS) control returns via a path 160 tothe idle state 150. Control will also return to the idle state 150 when27 seconds have passed in the move up state 154 without receiving an uplimit signal UL. This last mentioned condition is a fault condition,since door travel time should never be as long as 27 seconds.

When control is in the idle state 150 and a command signal CMD-P isreceived while the door 14 is up (UL), control passes via a path 162 tothe move down state 164. In move down state 164, the down signals ofTable 1 are sent to relays 130 through 132 and a loop 166 is enteredwhich will be exited if any of the signals AOBS, CMD or OBS are receivedor if 27 seconds pass in the move down state 164. When the signal DL isreceived without a force obstruction (OBS) having occurred, controlmoves from move down state 164 to the idle state 150 via a path 168.Should 27 seconds expire or one of the signals AOBS, OBS or CMD bereceived by the logic unit 101 while in the move down state 164, controlproceeds to a stop and wait state 170 via a path 172. Control pauses inthe stop and wait state 170 for one-half second then proceeds to themove up state 154, which is discussed above, via a path 174.

In the preceding description, control exits the idle state 150 inresponse to a command signal CMD-P from control unit 19. When a commandsignal CMD-R is received from receiver/decoder 106 while in the idlestate 150, control moves to a move up state 176 via a path 178 when thedown limit is present and moves to a move down state 180 via a path 182when the up limit signal UL is present. In move up state 176, the upsignals of Table 1 are sent to control relays 130 through 132 and apause of 1.2 seconds occurs in a loop 184. During the 1.2 second pause,other command signals CMD-R are ignored so that multiple transmissionsfrom remote transmitter 24 (FIG. 1) will not each be responded to as aseparate signal. Should the up limit signal UL occur while in the moveup state 176, control will return to the idle state 150 via a path 186.However, the more likely state change via a path 188 occurs when the 1.2second period expires, giving control to move up state 154, which hasbeen previously discussed.

The move down state 180 is entered from idle state 150 when the door 14is at its up limit (UL) and a CMD-R command is received. In move downstate 180, the down signals of Table 1 are generated and a 1.2 secondpause, similar to the 1.2 second pause of move up state 176, is insertedbefore transferring control to the previously discussed move down state154 via a path 190. Should the down limit signal DL be received while inthe move down state 180, control returns to the idle state 150 via apath 192. Also, if either a force obstruction (OBS) or infraredobstruction (AOBS) occurs while in the move down state 180, controlmoves to the stop and wait state 170 via a path 194.

The state diagram of FIG. 5 also includes a stop state 195 which isentered via a path 196 if an up limit signal (UL) is received in thestop and wait state 170, via a path 197 if a force obstruction signal(OBS) occurs in the move up state 176 and via a path 198 if either aforce obstruction (OBS) or a command CMD is received while in the moveup state 154. In the stop state 195, the stop signals of Table 1 aresent to control relays 130 through 132. As previously described,whenever the control relays 130 through 132 are commanded to stop doormovement, the motor shaft rotation is checked to make certain that themotor 211 has actually stopped. When a signal MOV indicating motor shaftrotation is sensed by logic unit 101 in the stop state 195, logic unit101 detects a fault and control moves via a path 199 to the move upstate 154 to raise the door 14 if possible. The up command sent to thecontrol relays 130 through 132 in this situation, is considered a faultcontrol signal intended to recover the garage door operator 10 from thedetected motor rotation fault. When no motor rotation is detected instop state 195, control will remain in stop state 195 until a commandCMD signal is received which moves control to the previously discussedmove down state 164 via path 193.

Any of the relays 130 through 132 can fail in the energized or in thenon-energized position due to faults in the relay e.g., 130, its drivecircuitry e.g., transistor 141 or the control signal source, e.g., logicunit 101. Should relay 130 fail in the non-energized position, the door14 will respond normally to signals UPMTR2 and DWNMTR from logic unit101 to raise and lower door 14. Alternatively, should relay 130 fail inthe energized position, the door 14 will only travel up. Both of thefailure states of relay 130 are safe since the door 14 either operatescorrectly or is being moved up. When the command down (Table 1) isgenerated with relay 130 failing in the energized position, both up anddown windings 225 and 227 are energized, stopping motor rotation.Thermal switch 229 protects from any overheating in this dual windingenergized mode by interrupting current to the windings 225 and 227.

Should relay 131 fail in the non-energized position, up and downmovement of the door 14 is still correctly controlled by signals UPMTR1and DWNMTR. Alternatively, should relay 131 fail in the energizedposition, the door 14 will travel up to the up limit and stop. No downmovement of the door 14 is then possible, which is a safe failure mode.

Should relay 132 fail in the non-energized position, the door 14 islimited to upward movement. Alternatively, should relay 132 fail in theenergized position, the door 14 will travel down during a stop command(Table 1). However, the continued movement during a stop command will besensed by the signal MOV and the door 14 will be raised to its up limit.

While a preferred embodiment of the invention has been illustrated, itwill be obvious to those skilled in the art that various modificationsand changes may be made thereto without departing from the scope of theinvention as defined in the appended Claims.

We claim:
 1. Apparatus for opening and closing a garage doorcomprising:a motor having a rotatable member for rotating in a firstdirection to open the garage door and in a second direction to close thegarage door; motor control circuitry responsive to motor controlcommands for selectively connecting electrical power to said motor tocause rotation of said rotatable member thereby opening and closing saidgarage door; control arrangements for selectively sending one of aplurality of motor control commands to said motor control circuitry,said motor control commands specifying one of rotation of said rotatablemember in said first direction, rotation of said rotatable member insaid second direction, and no rotation of said rotatable member;apparatus for sensing the rotation of said rotatable member after thesending of at least a predetermined one of said motor control commands;and said control arrangements send fault control signals to said motorcontrol circuitry when the rotation of said rotatable member sensed bysaid sensing apparatus is not in accordance with the rotation specifiedby said at least one predetermined motor control command.
 2. Theapparatus of claim 1 wherein said fault control signals comprise signalsspecifying no rotation of the rotatable member.
 3. The apparatus ofclaim 1 wherein said at least one predetermined motor control commandspecifies no rotation of said rotatable member and said fault controlsignals comprise signals specifying the rotation of said motor in saidfirst direction.
 4. Apparatus for opening and closing a garage doorcomprising:a motor having a rotatable member for rotating in a firstdirection to open the garage door and in a second direction to close thegarage door; control arrangements for selectively generating ones of aplurality of motor control commands, said motor control commandsspecifying one of at least rotation of said rotatable member in saidfirst direction, rotation of said rotatable member in said seconddirection, and no rotation of said rotatable member; motor controlcircuitry responsive to said motor control commands for selectivelyconnecting electrical power to said motor to cause rotation of saidrotatable member, thereby opening and closing said garage door;apparatus for sensing motor operation differing from generated motorcontrol commands as a malfunction in the response by said motor controlcircuitry to said motor control commands; and said control arrangementsbeing responsive to said sensing apparatus for reversing the directionof garage door travel when said garage door is closing due tomalfunction of said motor control circuitry.
 5. Apparatus for raisingand lowering a door comprising:a source of motor driving voltage; amotor having an up winding which, when energized by said motor drivingvoltage, raises said door and a down winding which, when energized bysaid motor driving voltage, lowers said door; control arrangements forselectively generating one of a plurality of motor control commands,said motor control commands specifying one of at least energizing saidmotor for upward movement of said door or for downward movement of saiddoor; motor control circuitry responsive to said motor control commandsfor selectively connecting said motor driving voltage to said up windingor connecting said motor driving voltage to said down winding; and saidcontrol arrangements being responsive to motor operation differing fromgenerated motor control commands as a malfunction in the operation ofsaid motor control circuitry for generating a motor control commandspecifying energizing said motor for upward movement to raise a closingdoor.
 6. An apparatus as recited in claim 5 wherein said controlarrangements are responsive to said motor control circuitrymalfunctioning and connecting said motor driving voltage to said downwinding when said motor control commands specify energizing said motorfor upward movement of said door, thereupon generating the motor controlcommand responsive to the malfunction in the operation of said motorcontrol circuitry for specifying energizing said motor for upwardmovement to raise the closing door.
 7. An apparatus as recited in claim5 wherein said control arrangements generate a motor control commandspecifying de-energizing said motor for stopping movement of said door.8. An apparatus as recited in claim 7 wherein said control arrangementsare responsive to said motor control circuitry malfunctioning andconnecting said motor driving voltage to said down winding when saidmotor control commands specify de-energizing said motor for stoppingmovement of said door, thereupon generating the motor control commandresponsive to the malfunction in the operation of said motor controlcircuitry for specifying energizing said motor for upward movement toraise the closing door.
 9. An apparatus as recited in claim 5 whereinsaid control arrangements are responsive to said motor driving voltagebeing applied to said down winding when said motor control commandsspecify energizing said motor for upward movement or stopping movementof said door, thereupon generating the motor control command responsiveto the malfunction in the operation of said motor control circuitry forspecifying energizing said motor for upward movement to raise theclosing door.
 10. An apparatus as recited in claim 5 wherein saidcontrol arrangements are responsive to downward movement of said doorwhen said motor control commands specify energizing said motor forupward movement or stopping movement of said door, thereupon generatingthe motor control command responsive to the malfunction in the operationof said motor control circuitry for specifying energizing said motor forupward movement to raise the closing door.
 11. Apparatus for raising andlowering a door comprising:a source of motor driving voltage; a motorhaving a motor winding which, when selectively energized by said motordriving voltage, raises and lowers said door; control arrangements forselectively generating one of a plurality of motor control commands,said motor control commands specifying one of at least energizing saidmotor for raising said door or for lowering said door, or specifyingde-energizing said motor windings for stopping movement of said door;motor control circuitry responsive to said motor control commands forselectively connecting said motor driving voltage to said motor forraising said door or connecting said motor driving voltage to said motorfor lowering said door; a sensing element for sensing motor operationdiffering from the specified motor control command and responsive tosaid motor driving voltage being applied to said motor windings forraising or lowering said door, and responsive to the de-energizing saidmotor windings for stopping movement of said door; and said controlarrangements being responsive to said sensing element for generating amotor control command specifying energizing said motor windings forraising said door when said sensing element responsive to said motordriving voltage senses motor operation differing from the specifiedmotor control command.
 12. An apparatus as recited in claim 11 whereinsaid control arrangements respond to the sensing element sensingdownward movement of said door when said motor control command specifiesenergizing said motor for upward movement of said door, thereupongenerating the motor control command for specifying energizing saidmotor for upward movement to raise the closing door.
 13. Apparatus forraising and lowering a door comprising:a source of motor drivingvoltage; a motor having an up winding which, when energized by saidmotor driving voltage, raises said door and a down winding which, whenenergized by said motor driving voltage, lowers said door; controlarrangements for selectively generating one of a plurality of motorcontrol commands, said motor control commands specifying one of at leastenergizing said motor for upward movement of said door or for downwardmovement of said door, or specifying de-energizing said motor forstopping movement of said door; motor control circuitry responsive tosaid motor control commands for selectively connecting said motordriving voltage to said up winding or connecting said motor drivingvoltage to said down winding; a sensing element for sensing motoroperation differing from the specified motor control command responsiveto said motor driving voltage being applied to said down winding fordownward movement of said door, responsive to said motor driving voltagebeing applied to said up winding for upward movement of said door, andresponsive to the de-energizing said motor for stopping movement of saiddoor; and said control arrangements being responsive to said sensingelement sensing downward movement of said door, where said motor controlcommand specified de-energizing said motor for stopping movement of saiddoor and for generating a motor control command specifying energizingsaid motor for upward movement to raise the closing door.
 14. Apparatusfor opening and closing a garage door comprising:a motor having arotatable member for rotating in a first direction to open the garagedoor and in a second direction to close the garage door; controlarrangements for selectively generating ones of a plurality of motorcontrol commands, said motor control commands specifying one of at leastrotation of said rotatable member in said first direction, rotation ofsaid rotatable member in said second direction, and no rotation of saidrotatable member; motor control circuitry responsive to said motorcontrol command specifying no rotation for selectively stopping rotationof said rotatable member to stop garage door movement; apparatus forsensing garage door movement while the motor control circuitry isstopping rotation of the rotatable member; and said control arrangementsresponsive to said sensing apparatus sensing garage door movement, whenno rotation was specified, for rotating said rotatable member in saidfirst direction to open the garage door.
 15. Apparatus for opening andclosing a garage door comprising:a motor having a rotatable member forrotating in a first direction to open the garage door and in a seconddirection to close the garage door; control arrangements for selectivelygenerating ones of a plurality of motor control commands, said motorcontrol commands specifying one of at least rotation of said rotatablemember in said first direction, rotation of said rotatable member insaid second direction, and no rotation of said rotatable member; motorcontrol circuitry for selectively connecting electrical power toenergize said motor for upward movement of said door, for connectingsaid electrical power to energize said motor for downward movement ofsaid door and for removing electrical power from said motor; said motorcontrol circuitry being responsive to said motor control commandspecifying no rotation of said control apparatus for stopping rotationof said rotatable member; apparatus for sensing garage door movementwhen no rotation is specified; and said control arrangements beingresponsive to said sensing apparatus for controlling the motor controlcircuitry to disconnect the electrical power from said motor forstopping upward or downward movement of said door when no rotation isspecified.
 16. A method for a garage door operating system includingmotor control circuitry which responds to motor control commands byenergizing a motor to raise, lower and stop the door, the methodcomprising:sending a first motor control command to the motor controlcircuitry, said first motor control command specifying one of raising,lowering or stopping the door; detecting a malfunction of the motorcontrol circuitry in response to the first motor control command bysensing door movement after the first motor control command is sent; andsending fault control signals to the motor control circuitry when thedetecting step determines that door movement is not in accordance withthe first motor control command.
 17. The method of claim 16 wherein thedetecting step comprises sensing the rotation of a rotatable member ofthe motor.
 18. The method of claim 16 wherein the fault control signalsspecify stopping the door.
 19. The method of claim 17 wherein the faultcontrol signals specify raising the door.
 20. A method for a garage dooroperating system including motor control circuitry which responds tomotor control commands by energizing a motor to raise, lower and stopthe door, the method comprising:sending a first motor control command tothe motor control circuitry, said first motor control command specifyingone of raising, lowering or stopping the door; detecting a malfunctionof the motor control circuitry in response to the first motor controlcommand by identifying incorrect energization of the motor resulting indoor movement not specified by the first motor control command; andsending a second motor control command to the motor control circuitry toraise the door when the detecting step determines that door movement isnot in accordance with the first motor control command.
 21. The methodof claim 20 wherein the determining step comprises sensing the rotationof a rotatable member of the motor.
 22. A method for a garage dooroperating system including motor control circuitry which responds tomotor control commands by energizing a motor to raise, lower and stopthe door, the method comprising:sending a first motor control command tothe motor control circuitry, specifying that the door should be stopped;sensing door movement after the first motor control command is sent todetect a malfunction of the motor control circuitry in response to thefirst motor control command; and sending a second motor control commandto the motor control circuitry to raise the door when the sensing stepdetermines that door movement is not in accordance with the first motorcontrol command.